Christian Regester, senior designer of technical products, works in the Forge on the Micro Puff ® Jacket. KYLE SPARKS © 2018 Patagonia, Inc. It all adds up to nothing. The Micro Puff ® Hoody Our lightest, most packable insulated jacket ever. After 4 years of fi eld testing, 830 hours of materials refi nement, 3 different names, and at least 6,000 vertical feet climbed on a single testing trip, we managed to create a jacket that solves one of the most perplexing problems in insulation: How do you make something that combines the best qualities of down and synthetic to create the ideal insulation formula? It all started with PlumaFill, a fi ber we discovered in 2007 that proved to be both highly compressible and warmer for its weight than any synthetic insulation we’d ever tested. We combined this with a pattern that took years to perfect and a quilting construction that allows heat to move freely inside the liner. This is the formula for creating a jacket that redefi nes insulation.